Support apparatus for a ceramic honeycomb element

Abstract

Disclosed is an apparatus for supporting a ceramic honeycomb element which is anisotropic in modulus of elasticity and in strength. The support apparatus comprises a shock absorber which is interposed between a casing and the honeycomb element so that a force of pressure acts on the honeycomb element in high-strength directions of the honeycomb structure thereof.

What is claimed is: 
     
       1. A reactor comprising: a hollow cylindrical ceramic honeycomb element containing a catalyst, having a number of rectangular holes defined by a pair of parallel wall groups intersecting each other perpendicularly and extending in the axis of the ceramic element;   a casing made of material having a higher thermal expansion coefficient than said ceramic element, and having a circular cross section, and surrounding said ceramic element, thus defining an annular space between the outer periphery of said ceramic element and the inner periphery of the casing; and   a ring-shaped filling member filled in the annular space so as to seal the annular space, having a uniform thickness and made of a material the thermal-expansion coefficient and elasticity of which increase in proportion to the density of the material, said filling member including,   at least two high-density portions located at each of two regions which are diametrically opposed with respect to the axis of the ceramic element and at which at least one of the wall groups of said ceramic element extend substantially normal to the filling member, and   at least two low-density portions located at each of two regions other than the regions at which the high-density portions are located;   whereby said high-density portions have a density higher than that of said low-density portions such that when said ceramic element is heated, the high-density portions expand more than the low-density portions and apply greater force to said ceramic element, such that the high-density portions firmly hold said ceramic element and seal the annular space, while the low-density portions seal the annular space in a manner that the low-density portions apply substantially less force to said ceramic element than the high-density portions.   
     
     
       2. The apparatus according to claim 1, wherein said filling member is a mat made of ceramic fibers. 
     
     
       3. A method of manufacturing an apparatus for supporting a hollow cylindrical ceramic honeycomb element having a circular cross section and having a number of rectangular holes defined by a pair of parallel wall groups intersecting each other perpendicularly and extending in the axis of the ceramic element, said method comprising the steps of: preparing a sheet member having a length equal to the circumference of the ceramic element and made of a material the thermal expansion coefficient and elasticity of which increase in proportion to the density at which it fills a limited space;   arranging a plurality of filling members on the sheet member, spaced apart at predetermined intervals in the lengthwise direction of the sheet member, each filling member formed of a predetermined number of laminated layers made of the same material as the sheet member;   compressing the filling member and the sheet member, thus forming a filling sheet which has a thickness uniform in the lengthwise direction of the sheet member and has high-density portions and low-density portions;   winding the filling sheet around the ceramic element, with at least one of the wall groups of the ceramic element extending substantially normal to the high-density portions of the filling sheet;   inserting the ceramic element with the filling members wound around the ceramic element, into a hollow cylindrical case made of metal so as to fill a space between the casing and the ceramic element and seal it; and   wherein when said ceramic element is heated, the high-density portions expand more than the low-density portions and apply greater force to said ceramic element, such that the high-density portions firmly hold said ceramic element and seal the annular space, while the low-density portions seal the annular space in a manner which apply a lower force to said ceramic element than said high-density portions.